# Draft California 2012 Integrated Report( 303(d) List/305(b) Report)

# Supporting Information

## Regional Board 6 - Lahontan Region

Water Body Name: | Crab Creek
Water Body ID: | CAR6282000020070828155012
Water Body Type: | River & Stream

DECISION ID | 22042 | Region 6
Crab Creek

Pollutant: | Acid Neutralizing Capacity
Final Listing Decision: | Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: | Do Not List on 303(d) list (TMDL required list)(2010)
Revision Status | Original
Impairment from Pollutant or Pollution: | Pollutant
Regional Board Staff Conclusion: | This pollutant was considered for placement on the section 303(d) list in a previous assessment cycle. No new information was reviewed for this current assessment cycle. Therefore, the previous conclusion remains unchanged, and is as follows: This pollutant is being considered for placement on the section 303(d) list under section 3.2 of the Listing Policy. Under section 3.2 a single line of evidence is necessary to assess listing status. One line of evidence is available in the administrative record to assess this pollutant. Acid Neutralizing Capacity (ANC) is equivalent to alkalinity, and the USEPA "Gold Book" criterion for alkalinity states that it should be greater than 20 mg/L CaCO3 unless natural alkalinity is lower. Only one ANC sample is available for Crab Creek, and it is below 20 mg/L. There is insufficient information to determine the natural range of ANC. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category. This conclusion is based on the staff findings that: 1. The data used satisfy the data quality requirements of section 6.1.4 of the Policy. 2. The data used do not satisfy the data quantity requirements of section 6.1.5 of the Policy. 3. It is not possible to determine whether the single sample exceeds the criterion. The minimum sample number requirements of Table 3.2 of the Listing Policy are not met. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
Regional Board Staff Decision Recommendation: | No new data were assessed for this assessment cycle. The conclusion reached in the previous cycle remains in same. The Regional Board will update this decision when new data and information become available in a future assessment cycle.

Line of Evidence (LOE) for Decision ID 22042, Acid Neutralizing Capacity | Region 6
Crab Creek
LOE ID: | 8284
Pollutant: | Acid Neutralizing Capacity
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | None
Beneficial Use: | Cold Freshwater Habitat
Number of Samples: | 1
Number of Exceedances: | 0
Data and Information Type: | Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: | The U.S. Geological Survey sampled Crab Creek under the Region 6 SWAMP program. One sample collected on March 21, 2003 was analyzed for ANC. The result was 7.7 mg/L CaCO3.
Data Reference: | 2007. SWAMP Data for the Mojave River Watershed
SWAMP Data: | SWAMP
Water Quality Objective/Criterion: | There are no California or federal standards or criteria for acid neutralizing capacity (ANC) per se. However, ANC is equivalent to alkalinity, and the U.S. Environmental Protection Agency "Gold Book" recommends alkalinity greater than 20 mg/L CaCO3 unless natural alkalinity is lower.
Objective/Criterion Reference: | Quality Criteria for Water 1986. United States Environmental Protection Agency. Office of Water. Regulations and Standards. Washington D.C. EPA 440/5-86-001.
Evaluation Guideline: |
Guideline Reference:
Spatial Representation: | One station, Crab Creek at Crab Flats Road near Lake Arrowhead, was sampled.
Temporal Representation: | One sample was collected on March 21, 2003.
Environmental Conditions: | Crab Creek is a tributary of Deep Creek, the largest tributary of the Mojave River, located in San Bernardino National Forest. Its headwaters are near the community of Green Valley Lake. In addition to the Cold Freshwater Habitat beneficial use, Crab Creek is designated for the Spawning, Reproduction and Development use.
QAPP Information: | The data meet the quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):

DECISION ID | 21877 | Region 6
Crab Creek

Pollutant: | Boron
Final Listing Decision: | Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: | Do Not List on 303(d) list (TMDL required list)(2010)
Revision Status | Original
Impairment from Pollutant or Pollution: | Pollutant
Regional Board Staff Conclusion: | This pollutant was considered for placement on the section 303(d) list in a previous assessment cycle. No new information was reviewed for this current assessment cycle. Therefore, the previous conclusion remains unchanged, and is as follows: This pollutant is being considered for placement on the section 303(d) list under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status. Two lines of evidence are available in the administrative record to assess this pollutant. None of the annual average datapoints exceed the site-specific water quality objective. None of the samples exceed the California State Notification Level criterion. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category. This conclusion is based on the staff findings that: 1. The data used satisfy the data quality requirements of section 6.1.4 of the Policy. 2. The data used do not satisfy the data quantity requirements of section 6.1.5 of the Policy. Quarterly samples do not capture the seasonal and annual variability expected in streamflows and constituent concentrations in streams of the Lahontan Region. 3. None of 4 annual average datapoints exceeded the site-specific objective. None of 8 samples exceeded the drinking water criterion and this does not exceed the allowable frequency listed in Table 3.1 of the Listing Policy. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
Regional Board Staff Decision Recommendation: | No new data were assessed for this assessment cycle. The conclusion reached in the previous cycle remains in same. The Regional Board will update this decision when new data and information become available in a future assessment cycle.

Line of Evidence (LOE) for Decision ID 21877, Boron | Region 6
Crab Creek
LOE ID: | 7809
Pollutant: | Boron
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | Dissolved
Beneficial Use: | Municipal & Domestic Supply
Number of Samples: | 8
Number of Exceedances: | 0
Data and Information Type: | Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: | The U.S. Geological Survey sampled boron under the Region 6 SWAMP program between 2001 and 2005.. Boron concentrations in 8 samples were all estimated values or below the detection level. The criterion was not exceeded.
Data Reference: | 2007. SWAMP Data for the Mojave River Watershed
SWAMP Data: | SWAMP
Water Quality Objective/Criterion: | The California State Notification Level criterion for boron is 1000 ug/L.
Objective/Criterion Reference: | Drinking Water Notification and Response Levels: An Overview
Evaluation Guideline: |
Guideline Reference:
Spatial Representation: | One station was sampled (Crab Creek at Crab Flats Road near Lake Arrowhead).
Temporal Representation: | One sample was collected in 2001, and 7 samples were collected quarterly between 2003 and 2005.
Environmental Conditions: | Crab Creek is a tributary of Deep Creek, the largest tributary of the Mojave River, located in San Bernardino National Forest. Its headwaters are near the community of Green Valley Lake. In addition to the Cold Freshwater Habitat beneficial use, Crab Creek is designated for the Spawning, Reproduction and Development use.
QAPP Information: | Data meet the quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):
Line of Evidence (LOE) for Decision ID 21877, Boron | Region 6
Crab Creek
LOE ID: | 5209
Pollutant: | Boron
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | Dissolved
Beneficial Use: | Cold Freshwater Habitat
Number of Samples: | 4
Number of Exceedances: | 0
Data and Information Type: | Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: | The U.S. Geological Survey sampled boron under the Region 6 SWAMP program between 2001 and 2005.. Boron concentrations in 8 samples were all estimated values or below the detection level. This makes calculation of annual averages infeasible. The objective was not exceeded.
Data Reference: | 2007. SWAMP Data for the Mojave River Watershed
SWAMP Data: | SWAMP
Water Quality Objective/Criterion: | The applicable site-specific objectives are those for Deep Creek Station 5, from Lahontan Basin Plan Table 3-21: The boron objective includes an annual average of 0.05 mg/L (or 50 ug/L) and a 90th percentile value of 0.07 mg/L (or 70 ug/L).
Objective/Criterion Reference: | Water Quality Control Plan for the Lahontan Region (as amended)
Evaluation Guideline: |
Guideline Reference:
Spatial Representation: | One station was sampled (Crab Creek at Crab Flats Road near Lake Arrowhead).
Temporal Representation: | One sample was collected in 2001, and 7 samples were collected quarterly between 2003 and 2005.
Environmental Conditions: | Crab Creek is a tributary of Deep Creek, the largest tributary of the Mojave River, located in San Bernardino National Forest. Its headwaters are near the community of Green Valley Lake. In addition to the Cold Freshwater Habitat beneficial use, Crab Creek is designated for the Spawning, Reproduction and Development use.
QAPP Information: | Data meet the quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):

DECISION ID | 20802 | Region 6
Crab Creek

Pollutant: | Chloride
Final Listing Decision: | Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: | Do Not List on 303(d) list (TMDL required list)(2010)
Revision Status | Original
Impairment from Pollutant or Pollution: | Pollutant
Regional Board Staff Conclusion: | This pollutant was considered for placement on the section 303(d) list in a previous assessment cycle. No new information was reviewed for this current assessment cycle. Therefore, the previous conclusion remains unchanged, and is as follows: This pollutant is being considered for placement on the section 303(d) list under section 3.2 of the Listing Policy. Under section 3.2 a single line of evidence is necessary to assess listing status. Two lines of evidence are available in the administrative record to assess this pollutant. None of the samples or annual average datapoints exceed the applicable water quality objectives. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category. This conclusion is based on the staff findings that: 1. The data used satisfy the data quality requirements of section 6.1.4 of the Policy. 2. The data used do not satisfy the data quantity requirements of section 6.1.5 of the Policy. Quarterly samples do not capture the seasonal and annual variability expected in streamflows and constituent concentrations in streams of the Lahontan Region. 3. None of 11 individual samples or 5 annual average datapoints exceeded the applicable water quality objectives and this does not exceed the allowable frequency listed in Table 3.2 of the Listing Policy. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
Regional Board Staff Decision Recommendation: | No new data were assessed for this assessment cycle. The conclusion reached in the previous cycle remains in same. The Regional Board will update this decision when new data and information become available in a future assessment cycle.

Line of Evidence (LOE) for Decision ID 20802, Chloride | Region 6
Crab Creek
LOE ID: | 5210
Pollutant: | Chloride
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | Dissolved
Beneficial Use: | Cold Freshwater Habitat
Number of Samples: | 5
Number of Exceedances: | 0
Data and Information Type: | Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: | The U.S. Geological Survey sampled chloride under the Region 6 SWAMP program between 2001 and 2005. Chloride concentrations in 11 quarterly samples ranged from 1.19 to 3.42 mg/L. The annual average objective was not exceeded in the five years of sampling..
Data Reference: | 2007. SWAMP Data for the Mojave River Watershed
SWAMP Data: | SWAMP
Water Quality Objective/Criterion: | The applicable site-specific objectives are those for Deep Creek Station 5, from Lahontan Basin Plan Table 3-21: The chloride objective includes an annual average of 9.1 mg/L and a 90th percentile value of 16.0 mg/L.
Objective/Criterion Reference: | Water Quality Control Plan for the Lahontan Region (as amended)
Evaluation Guideline: |
Guideline Reference:
Spatial Representation: | One station was sampled (Crab Creek at Crab Flats Road near Lake Arrowhead).
Temporal Representation: | Eleven quarterly samples were collected between 2001 and 2005.
Environmental Conditions: | Crab Creek is a tributary of Deep Creek, the largest tributary of the Mojave River, located in San Bernardino National Forest. Its headwaters are near the community of Green Valley Lake. In addition to the Cold Freshwater Habitat beneficial use, Crab Creek is designated for the Spawning, Reproduction and Development use.
QAPP Information: | Data meet the quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):
Line of Evidence (LOE) for Decision ID 20802, Chloride | Region 6
Crab Creek
LOE ID: | 5211
Pollutant: | Chloride
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | Dissolved
Beneficial Use: | Municipal & Domestic Supply
Number of Samples: | 11
Number of Exceedances: | 0
Data and Information Type: | Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: | The U.S. Geological Survey sampled chloride under the Region 6 SWAMP program between 2001 and 2005. Chloride concentrations in 11 samples ranged from 1.19 to 3.42 mg/L. The MCL was not exceeded.
Data Reference: | 2007. SWAMP Data for the Mojave River Watershed
SWAMP Data: | SWAMP
Water Quality Objective/Criterion: | California Maximum Contaminant Levels (MCLs) apply to ambient waters under the Lahontan Basin Plan's "Chemical Constituents" objective. The MCL for chloride is 250 mg/L.
Objective/Criterion Reference: | Water Quality Control Plan for the Lahontan Region (as amended)
Evaluation Guideline: |
Guideline Reference:
Spatial Representation: | One station was sampled (Crab Creek at Crab Flats Road near Lake Arrowhead).
Temporal Representation: | Eleven quarterly samples were collected between 2001 and 2005.
Environmental Conditions: | Crab Creek is a tributary of Deep Creek, the largest tributary of the Mojave River, located in San Bernardino National Forest. Its headwaters are near the community of Green Valley Lake.
QAPP Information: | Data meet the quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):

DECISION ID | 21708 | Region 6
Crab Creek

Pollutant: | Dissolved oxygen saturation
Final Listing Decision: | Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: | Do Not List on 303(d) list (TMDL required list)(2010)
Revision Status | Original
Impairment from Pollutant or Pollution: | Pollutant
Regional Board Staff Conclusion: | This pollutant was considered for placement on the section 303(d) list in a previous assessment cycle. No new information was reviewed for this current assessment cycle. Therefore, the previous conclusion remains unchanged, and is as follows: This pollutant is being considered for placement on the section 303(d) list under section 3.2 of the Listing Policy. Under section 3.2 a single line of evidence is necessary to assess listing status. One line of evidence is available in the administrative record to assess this pollutant. None of the samples exceed the water quality objective. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category. This conclusion is based on the staff findings that: 1. The data used satisfy the data quality requirements of section 6.1.4 of the Policy. 2. The data used do not satisfy the data quantity requirements of section 6.1.5 of the Policy. Only three samples are available. 3. None of 3 samples exceeded the water quality objective and this does not meet the minimum sample number requirement or exceed the allowable frequency listed in Table 3.2 of the Listing Policy. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
Regional Board Staff Decision Recommendation: | No new data were assessed for this assessment cycle. The conclusion reached in the previous cycle remains in same. The Regional Board will update this decision when new data and information become available in a future assessment cycle.

Line of Evidence (LOE) for Decision ID 21708, Dissolved oxygen saturation | Region 6
Crab Creek
LOE ID: | 5732
Pollutant: | Dissolved oxygen saturation
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | Dissolved
Beneficial Use: | Cold Freshwater Habitat
Number of Samples: | 3
Number of Exceedances: | 0
Data and Information Type: | Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: | The U.S. Geological Survey sampled percent saturation of dissolved oxygen quarterly under the Region 6 SWAMP program between November 2004 and July 2005. Three samples had percent saturation values of 97, 97 and 98 percent.
Data Reference: | Water Quality Control Plan for the Lahontan Region (as amended)
| 2007. SWAMP Data for the Mojave River Watershed
SWAMP Data: | SWAMP
Water Quality Objective/Criterion: | The Lahontan Basin Plan's regionwide objective for dissolved oxygen provides that percent saturation shall not be depressed more than 10 percent nor shall the minimum dissolved oxygen concentration be less than 80 percent of saturation.
Objective/Criterion Reference: | Water Quality Control Plan for the Lahontan Region (as amended)
Evaluation Guideline: |
Guideline Reference:
Spatial Representation: | One station was sampled (Crab Creek at Crab Flats Road near Lake Arrowhead).
Temporal Representation: | Three quarterly measurements of percent saturation were taken between November 2004 and July 2005.
Environmental Conditions: | Crab Creek is a tributary of Deep Creek, the largest tributary of the Mojave River, located in San Bernardino National Forest. Its headwaters are near the community of Green Valley Lake. In addition to the Cold Freshwater Habitat beneficial use, Crab Creek is designated for the Spawning, Reproduction and Development use.
QAPP Information: | Data meet the quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):

DECISION ID | 21236 | Region 6
Crab Creek

Pollutant: | Fluoride
Final Listing Decision: | Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: | Do Not List on 303(d) list (TMDL required list)(2010)
Revision Status | Original
Impairment from Pollutant or Pollution: | Pollutant
Regional Board Staff Conclusion: | This pollutant was considered for placement on the section 303(d) list in a previous assessment cycle. No new information was reviewed for this current assessment cycle. Therefore, the previous conclusion remains unchanged, and is as follows: This pollutant is being considered for placement on the section 303(d) list under section 3.2 of the Listing Policy. Under section 3.2 a single line of evidence is necessary to assess listing status. Two lines of evidence are available in the administrative record to assess this pollutant. None of the samples or annual average datapoints exceed the applicable water quality objectives. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category. This conclusion is based on the staff findings that: 1. The data used satisfy the data quality requirements of section 6.1.4 of the Policy. 2. The data used satisfy the data quantity requirements of section 6.1.5 of the Policy. 3. None of 8 samples or 5 annual average datapoints exceeded the applicable water quality objectives and this does not exceed the allowable frequency listed in Table 3.2 of the Listing Policy. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
Regional Board Staff Decision Recommendation: | No new data were assessed for this assessment cycle. The conclusion reached in the previous cycle remains in same. The Regional Board will update this decision when new data and information become available in a future assessment cycle.

Line of Evidence (LOE) for Decision ID 21236, Fluoride | Region 6
Crab Creek
LOE ID: | 5215
Pollutant: | Fluoride
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | Dissolved
Beneficial Use: | Municipal & Domestic Supply
Number of Samples: | 8
Number of Exceedances: | 0
Data and Information Type: | Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: | The U.S. Geological Survey sampled fluoride under the Region 6 SWAMP program between 2001 and 2005 Fluoride concentrations in 7 of 8 samples were estimates or below the detection level. The remaining sample was 0.1 mg/L. The MCL was not violated.
Data Reference: | 2007. SWAMP Data for the Mojave River Watershed
SWAMP Data: | SWAMP
Water Quality Objective/Criterion: | California Maximum Contaminant Levels (MCLs) apply to ambient waters under the Lahontan Basin Plan's "Chemical Constituents" objective. The MCL for fluoride is 2 mg/L.
Objective/Criterion Reference: | Water Quality Control Plan for the Lahontan Region (as amended)
Evaluation Guideline: |
Guideline Reference:
Spatial Representation: | One station was sampled (Crab Creek at Crab Flats Road near Lake Arrowhead).
Temporal Representation: | Eight samples were taken between 2001 and 2005.
Environmental Conditions: | Crab Creek is a tributary of Deep Creek, the largest tributary of the Mojave River, located in San Bernardino National Forest. Its headwaters are near the community of Green Valley Lake.
QAPP Information: | Data meet the quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):
Line of Evidence (LOE) for Decision ID 21236, Fluoride | Region 6
Crab Creek
LOE ID: | 5214
Pollutant: | Fluoride
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | Dissolved
Beneficial Use: | Cold Freshwater Habitat
Number of Samples: | 5
Number of Exceedances: | 0
Data and Information Type: | Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: | The U.S. Geological Survey sampled fluoride under the Region 6 SWAMP program between 2001 and 2005 Fluoride concentrations in 7 of 8 samples were estimates or below the detection level. The remaining sample was 0.1 mg/L. The annual average objective was not violated.
Data Reference: | 2007. SWAMP Data for the Mojave River Watershed
SWAMP Data: | SWAMP
Water Quality Objective/Criterion: | The site specific objective for Deep Creek Station 5, from Lahontan Basin Plan Table 3-21, applies to Crab Creek. It includes an annual average of 0.10 mg/L and a 90th percentile value of 0.19 mg/L
Objective/Criterion Reference: | Water Quality Control Plan for the Lahontan Region (as amended)
Evaluation Guideline: |
Guideline Reference:
Spatial Representation: | One station was sampled (Crab Creek at Crab Flats Road near Lake Arrowhead).
Temporal Representation: | Eight samples were taken between 2001 and 2005. Five annual average calculations were done.
Environmental Conditions: | Crab Creek is a tributary of Deep Creek, the largest tributary of the Mojave River, located in San Bernardino National Forest. Its headwaters are near the community of Green Valley Lake. In addition to the Cold Freshwater Habitat beneficial use, Crab Creek is designated for the Spawning, Reproduction and Development use.
QAPP Information: | Data meet the quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):

DECISION ID | 21787 | Region 6
Crab Creek

Pollutant: | Nitrate
Final Listing Decision: | Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: | Do Not List on 303(d) list (TMDL required list)(2010)
Revision Status | Original
Impairment from Pollutant or Pollution: | Pollutant
Regional Board Staff Conclusion: | This pollutant was considered for placement on the section 303(d) list in a previous assessment cycle. No new information was reviewed for this current assessment cycle. Therefore, the previous conclusion remains unchanged, and is as follows: This pollutant is being considered for placement on the section 303(d) list under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status. Two lines of evidence are available in the administrative record to assess this pollutant. None of the samples or annual average datapoints exceed the applicable water quality objectives. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category. This conclusion is based on the staff findings that: 1. The data used satisfy the data quality requirements of section 6.1.4 of the Policy. 2. The data used do not satisfy the data quantity requirements of section 6.1.5 of the Policy. Quarterly samples do not capture the seasonal and annual variability expected in streamflows and constituent concentrations in streams of the Lahontan Region. 3. None of 5 annual average datapoints exceeded the site-specific objective. None of 11 samples exceeded the California Maximum Contaminant Level and this does not exceed the allowable frequency listed in Table 3.1 of the Listing Policy. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
Regional Board Staff Decision Recommendation: | No new data were assessed for this assessment cycle. The conclusion reached in the previous cycle remains in same. The Regional Board will update this decision when new data and information become available in a future assessment cycle.

Line of Evidence (LOE) for Decision ID 21787, Nitrate | Region 6
Crab Creek
LOE ID: | 7807
Pollutant: | Nitrate
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | Dissolved
Beneficial Use: | Municipal & Domestic Supply
Number of Samples: | 11
Number of Exceedances: | 0
Data and Information Type: | Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: | The U.S. Geological Survey sampled Crab Creek under the Region 6 SWAMP program between 2001 and 2005. Of 11 calculated values for nitrate (as nitrate), 6 were estimated value. Nitrate concentrations in the remaining samples ranged from 0 to 0.004 mg/L. The MCL was not exceeded.
Data Reference: | 2007. SWAMP Data for the Mojave River Watershed
SWAMP Data: | SWAMP
Water Quality Objective/Criterion: | California Maximum Contaminant Levels (MCLs) apply to ambient waters under the Lahontan Basin Plan's "Chemical Constituents" objective. The MCL for nitrate is 45 mg/L expressed "as nitrate", equivalent to 10 mg/L expressed "as nitrogen".
Objective/Criterion Reference: | Water Quality Control Plan for the Lahontan Region (as amended)
Evaluation Guideline: |
Guideline Reference:
Spatial Representation: | One station was sampled (Crab Creek at Crab Flats Road near Lake Arrowhead).
Temporal Representation: | Eleven quarterly samples (1 to 3 per year) were collected between 2001 and 2005 for nitrite plus nitrate and eleven samples were collected for nitrite. Eleven calculations to obtain nitrate concentrations were done.
Environmental Conditions: | Crab Creek is a tributary of Deep Creek, the largest tributary of the Mojave River, located in San Bernardino National Forest. Its headwaters are near the community of Green Valley Lake.
QAPP Information: | Data meet the quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):
Line of Evidence (LOE) for Decision ID 21787, Nitrate | Region 6
Crab Creek
LOE ID: | 7808
Pollutant: | Nitrate
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | Dissolved
Beneficial Use: | Cold Freshwater Habitat
Number of Samples: | 5
Number of Exceedances: | 0
Data and Information Type: | Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: | The U.S. Geological Survey sampled Crab Creek under the Region 6 SWAMP program between 2001 and 2005. Of 11 calculated values for nitrate (as nitrate), 6 were estimated value. Nitrate concentrations in the remaining samples ranged from 0 to 0.004 mg/L. The site-specific annual average objective was not exceeded.
Data Reference: | 2007. SWAMP Data for the Mojave River Watershed
SWAMP Data: | SWAMP
Water Quality Objective/Criterion: | The applicable site-specific objective for nitrate (as nitrate) in Table 3-21 of the Lahontan Basin Plan is the objective for Deep Creek Station 5. It includes an annual average of 0.2 mg/L and a 90th percentile value of 0.6 mg/L.
Objective/Criterion Reference: | Water Quality Control Plan for the Lahontan Region (as amended)
Evaluation Guideline: |
Guideline Reference:
Spatial Representation: | One station was sampled (Crab Creek at Crab Flats Road near Lake Arrowhead).
Temporal Representation: | Eleven quarterly samples (1 to 3 per year) were collected for nitrite plus nitrate, and eleven samples for nitrite. Eleven calculations for nitrate were done between 2001 and 2005.
Environmental Conditions: | Crab Creek is a tributary of Deep Creek, the largest tributary of the Mojave River, located in San Bernardino National Forest. Its headwaters are near the community of Green Valley Lake.
QAPP Information: | Data meet the quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):

DECISION ID | 21734 | Region 6
Crab Creek

Pollutant: | Nitrate/Nitrite (Nitrite + Nitrate as N)
Final Listing Decision: | Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: | Do Not List on 303(d) list (TMDL required list)(2010)
Revision Status | Original
Impairment from Pollutant or Pollution: | Pollutant
Regional Board Staff Conclusion: | This pollutant was considered for placement on the section 303(d) list in a previous assessment cycle. No new information was reviewed for this current assessment cycle. Therefore, the previous conclusion remains unchanged, and is as follows: This pollutant is being considered for placement on the section 303(d) list under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status. One line of evidence is available in the administrative record to assess this pollutant. None of the samples exceed the water quality objective. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category. This conclusion is based on the staff findings that: 1. The data used satisfy the data quality requirements of section 6.1.4 of the Policy. 2. The data used do not satisfy the data quantity requirements of section 6.1.5 of the Policy. Quarterly samples do not capture the seasonal and annual variability expected in streamflows and constituent concentrations in streams of the Lahontan Region. 3. None of 11 samples exceeded the Maximum Contaminant Level and this does not exceed the allowable frequency listed in Table 3.1 of the Listing Policy. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
Regional Board Staff Decision Recommendation: | No new data were assessed for this assessment cycle. The conclusion reached in the previous cycle remains in same. The Regional Board will update this decision when new data and information become available in a future assessment cycle.

Line of Evidence (LOE) for Decision ID 21734, Nitrate/Nitrite (Nitrite + Nitrate as N) | Region 6
Crab Creek
LOE ID: | 7805
Pollutant: | Nitrate/Nitrite (Nitrite + Nitrate as N)
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | Dissolved
Beneficial Use: | Municipal & Domestic Supply
Number of Samples: | 11
Number of Exceedances: | 0
Data and Information Type: | Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: | The U.S. Geological Survey sampled Crab Creek under the Region 6 SWAMP program between 2001 and 2005. Of 11 samples for nitrite plus nitrate, 6 had concentrations below the detection level. The remainder of the samples ranged from 0.001 to 0.004 mg/L. The MCL was not exceeded.
Data Reference: | 2007. SWAMP Data for the Mojave River Watershed
SWAMP Data: | SWAMP
Water Quality Objective/Criterion: | California Maximum Contaminant Levels (MCLs) apply to ambient waters under the Lahontan Basin Plan's "Chemical Constituents" objective. The MCL for nitrite plus nitrate is 10 mg/L, expressed "as N."
Objective/Criterion Reference: | Water Quality Control Plan for the Lahontan Region (as amended)
Evaluation Guideline: |
Guideline Reference:
Spatial Representation: | One station was sampled (Crab Creek at Crab Flats Road near Lake Arrowhead).
Temporal Representation: | Eleven quarterly samples (1 to 3 per year) were collected between 2001 and 2005.
Environmental Conditions: | Crab Creek is a tributary of Deep Creek, the largest tributary of the Mojave River, located in San Bernardino National Forest. Its headwaters are near the community of Green Valley Lake.
QAPP Information: | Data meet the quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):

DECISION ID | 21735 | Region 6
Crab Creek

Pollutant: | Nitrite
Final Listing Decision: | Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: | Do Not List on 303(d) list (TMDL required list)(2010)
Revision Status | Original
Impairment from Pollutant or Pollution: | Pollutant
Regional Board Staff Conclusion: | This pollutant was considered for placement on the section 303(d) list in a previous assessment cycle. No new information was reviewed for this current assessment cycle. Therefore, the previous conclusion remains unchanged, and is as follows: This pollutant is being considered for placement on the section 303(d) list under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status. One line of evidence is available in the administrative record to assess this pollutant. None of the samples exceed the California Maximum Contaminant Level. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category. This conclusion is based on the staff findings that: 1. The data used satisfy the data quality requirements of section 6.1.4 of the Policy. 2. The data used do not satisfy the data quantity requirements of section 6.1.5 of the Policy. Quarterly samples do not capture the seasonal and annual variability expected in streamflows and constituent concentrations in streams of the Lahontan Region. 3. None of 11 samples exceeded the California Maximum Contaminant Level and this does not exceed the allowable frequency listed in Table 3.1 of the Listing Policy. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
Regional Board Staff Decision Recommendation: | No new data were assessed for this assessment cycle. The conclusion reached in the previous cycle remains in same. The Regional Board will update this decision when new data and information become available in a future assessment cycle.

Line of Evidence (LOE) for Decision ID 21735, Nitrite | Region 6
Crab Creek
LOE ID: | 7806
Pollutant: | Nitrite
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | Dissolved
Beneficial Use: | Municipal & Domestic Supply
Number of Samples: | 11
Number of Exceedances: | 0
Data and Information Type: | Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: | The U.S. Geological Survey sampled Crab Creek under the Region 6 SWAMP program between 2001 and 2005. Of 11 samples for nitrite, 5 had concentrations below the detection level and one was an estimated value. The nitrite concentration in each of the remaining samples was 0.001 mg/L. The MCL was not exceeded.
Data Reference: | 2007. SWAMP Data for the Mojave River Watershed
SWAMP Data: | SWAMP
Water Quality Objective/Criterion: | California Maximum Contaminant Levels (MCLs) apply to ambient waters under the Lahontan Basin Plan's "Chemical Constituents" objective. The MCL for nitrite is 1 mg/L.
Objective/Criterion Reference: | Water Quality Control Plan for the Lahontan Region (as amended)
Evaluation Guideline: |
Guideline Reference:
Spatial Representation: | One station was sampled (Crab Creek at Crab Flats Road near Lake Arrowhead).
Temporal Representation: | Eleven quarterly samples (1 to 3 per year) were collected between 2001 and 2005.
Environmental Conditions: | Crab Creek is a tributary of Deep Creek, the largest tributary of the Mojave River, located in San Bernardino National Forest. Its headwaters are near the community of Green Valley Lake.
QAPP Information: | Data meet the quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):

DECISION ID | 21178 | Region 6
Crab Creek

Pollutant: | Oxygen, Dissolved
Final Listing Decision: | Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: | Do Not List on 303(d) list (TMDL required list)(2010)
Revision Status | Original
Impairment from Pollutant or Pollution: | Pollutant
Regional Board Staff Conclusion: | This pollutant was considered for placement on the section 303(d) list in a previous assessment cycle. No new information was reviewed for this current assessment cycle. Therefore, the previous conclusion remains unchanged, and is as follows: This pollutant is being considered for placement on the section 303(d) list under section 3.2 of the Listing Policy. Under section 3.2 a single line of evidence is necessary to assess listing status. One line of evidence is available in the administrative record to assess this pollutant. Three of the samples exceed the water quality objective. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category. This conclusion is based on the staff findings that: 1. The data used satisfy the data quality requirements of section 6.1.4 of the Policy. 2. The data used do not satisfy the data quantity requirements of section 6.1.5 of the Policy. Only ten samples were collected over a 5 year period and this sampling frequency is inadequate to document diel, seasonal, annual and interannual variations in dissolved oxygen concentrations. 3. Three of 10 samples exceeded the water quality objective and this does not exceed the allowable frequency listed in Table 3.2 of the Listing Policy. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
Regional Board Staff Decision Recommendation: | No new data were assessed for this assessment cycle. The conclusion reached in the previous cycle remains in same. The Regional Board will update this decision when new data and information become available in a future assessment cycle.

Line of Evidence (LOE) for Decision ID 21178, Oxygen, Dissolved | Region 6
Crab Creek
LOE ID: | 5213
Pollutant: | Oxygen, Dissolved
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | Dissolved
Beneficial Use: | Cold Freshwater Habitat
Number of Samples: | 10
Number of Exceedances: | 3
Data and Information Type: | Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: | The U.S. Geological Survey sampled dissolved oxygen under the Region 6 SWAMP program between 2001 and 2005. Dissolved oxygen concentrations in 10 samples ranged from 6.7 to 10.3 mg/L. Three samples had concentrations below the 1-day minimum objective.
Data Reference: | 2007. SWAMP Data for the Mojave River Watershed
SWAMP Data: | SWAMP
Water Quality Objective/Criterion: | The 1-day minimum objective (from Lahontan Basin Plan Table 3-6) is 8 mg/L.
Objective/Criterion Reference: | Water Quality Control Plan for the Lahontan Region (as amended)
Evaluation Guideline: |
Guideline Reference:
Spatial Representation: | One station was sampled (Crab Creek at Crab Flats Road near Lake Arrowhead).
Temporal Representation: | Ten quarterly measurements of dissolved oxygen (1 to 3 per year) were taken between 2001 and 2005.
Environmental Conditions: | Crab Creek is a tributary of Deep Creek, the largest tributary of the Mojave River, located in San Bernardino National Forest. Its headwaters are near the community of Green Valley Lake. In addition to the Cold Freshwater Habitat beneficial use, Crab Creek is designated for the Spawning, Reproduction and Development use.
QAPP Information: | Data meet the quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):

DECISION ID | 21238 | Region 6
Crab Creek

Pollutant: | Phosphate
Final Listing Decision: | Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: | Do Not List on 303(d) list (TMDL required list)(2010)
Revision Status | Original
Impairment from Pollutant or Pollution: | Pollutant
Regional Board Staff Conclusion: | This pollutant was considered for placement on the section 303(d) list in a previous assessment cycle. No new information was reviewed for this current assessment cycle. Therefore, the previous conclusion remains unchanged, and is as follows: This pollutant is being considered for placement on the section 303(d) list under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status. One line of evidence is available in the administrative record to assess this pollutant. None of the samples exceed the water quality objective. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category. This conclusion is based on the staff findings that: 1. The data used satisfy the data quality requirements of section 6.1.4 of the Policy. 2. The data used do not satisfy the data quantity requirements of section 6.1.5 of the Policy. Quarterly samples do not capture the seasonal and annual variability expected in streamflows and constituent concentrations in streams of the Lahontan Region. 3. None of five annual average datapoints exceeded the site-specific water quality objective and this does not exceed the allowable frequency listed in Table 3.1 of the Listing Policy. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
Regional Board Staff Decision Recommendation: | No new data were assessed for this assessment cycle. The conclusion reached in the previous cycle remains in same. The Regional Board will update this decision when new data and information become available in a future assessment cycle.

Line of Evidence (LOE) for Decision ID 21238, Phosphate | Region 6
Crab Creek
LOE ID: | 5217
Pollutant: | Phosphate
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | Dissolved
Beneficial Use: | Cold Freshwater Habitat
Number of Samples: | 5
Number of Exceedances: | 0
Data and Information Type: | Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: | The U.S. Geological Survey sampled phosphorus under the Region 6 SWAMP program between 2002 and 2005. Reported phosphate "as P" concentrations in 10 samples ranged from below the detection level (5 samples) to 0.01 mg/L. Calculated phosphate "as phosphate" concentrations for 10 samples ranged from below the detection level to 0.031 mg/L. A single sample analyzed for "dissolved hydrolyzable P + PO4" was below the detection level. The objective was not violated.
Data Reference: | 2007. SWAMP Data for the Mojave River Watershed
SWAMP Data: | SWAMP
Water Quality Objective/Criterion: | The site-specific numeric objectives for Deep Creek Station 5, from Basin Plan Table 3-21, apply to Crab Creek. The : annual average objective for total dissolved orthophosphate is 0.05 mg/L and the 90th percentile value is 0.13 mg/L.
Objective/Criterion Reference: | Water Quality Control Plan for the Lahontan Region (as amended)
Evaluation Guideline: |
Guideline Reference:
Spatial Representation: | One station was sampled (Crab Creek at Crab Flats Road near Lake Arrowhead).
Temporal Representation: | Ten quarterly samples reported "as P" were collected between 2002 and 2005 and 10 calculations for phosphate "as phosphate" were done. Five annual average calculations for phosphate "as phosphate" were done. A single sample, collected on 2/5/2002, was analyzed for dissolved hydrolyzable P plus PO4.
Environmental Conditions: | Crab Creek is a tributary of Deep Creek, the largest tributary of the Mojave River, located in San Bernardino National Forest. Its headwaters are near the community of Green Valley Lake. In addition to the Cold Freshwater Habitat beneficial use, Crab Creek is designated for the Spawning, Reproduction and Development use.
QAPP Information: | Data meet the quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):

DECISION ID | 22018 | Region 6
Crab Creek

Pollutant: | Phosphorus
Final Listing Decision: | Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: | Do Not List on 303(d) list (TMDL required list)(2010)
Revision Status | Original
Impairment from Pollutant or Pollution: | Pollutant
Regional Board Staff Conclusion: | This pollutant was considered for placement on the section 303(d) list in a previous assessment cycle. No new information was reviewed for this current assessment cycle. Therefore, the previous conclusion remains unchanged, and is as follows: This pollutant is being considered for placement on the section 303(d) list under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status. One line of evidence is available in the administrative record to assess this pollutant. No biological data are available to determine whether any of the samples exceeds the water quality objective. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category. This conclusion is based on the staff findings that: 1. 1. The data used do not satisfy the data quality requirements of section 6.1.4 of the Policy due to an error in the SWAMP QAPP regarding holding times for total phosphorus samples.. 2. The data used do not satisfy the data quantity requirements of section 6.1.5 of the Policy. Quarterly samples do not capture the seasonal and annual variability expected in streamflows and constituent concentrations in streams of the Lahontan Region. 3. No biological data are available for assessment of compliance with the objective for biostimulatory substances. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
Regional Board Staff Decision Recommendation: | No new data were assessed for this assessment cycle. The conclusion reached in the previous cycle remains in same. The Regional Board will update this decision when new data and information become available in a future assessment cycle.

Line of Evidence (LOE) for Decision ID 22018, Phosphorus | Region 6
Crab Creek
LOE ID: | 5708
Pollutant: | Phosphorus
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | Total
Beneficial Use: | Cold Freshwater Habitat
Number of Samples: | 7
Number of Exceedances: | 0
Data and Information Type: | Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: | The U.S. Geological Survey sampled total phosphorus in Crab Creek under the Region 6 SWAMP program between 2002 and 2005. Concentrations in 7 samples ranged from below the detection level (3 samples) to 0.025 mg/L. No data on algae or macrophytes are available for assessment of compliance with the biostimulatory substances objective.
Data Reference: | 2007. SWAMP Data for the Mojave River Watershed
SWAMP Data: | SWAMP
Water Quality Objective/Criterion: | The Lahontan Basin Plan does not include a site-specific objective (SSO) for total phosphorus in Crab Creek. (The SSO for phosphate is assessed in a separate line of evidence.) The narrative objective for biostimulatory substances states: "Waters shall not contain biostimulatory substances in concentrations that promote aquatic growths to the extent that such growths cause nuisance or adversely affect the water for beneficial uses."
Objective/Criterion Reference: | Water Quality Control Plan for the Lahontan Region (as amended)
Evaluation Guideline: |
Guideline Reference:
Spatial Representation: | One station was sampled (Crab Creek at Crab Flats Road near Lake Arrowhead).
Temporal Representation: | Seven quarterly samples (1 to 3 per year) were collected between 2002 and 2005.
Environmental Conditions: | Crab Creek is a tributary of Deep Creek, the largest tributary of the Mojave River, located in San Bernardino National Forest. Its headwaters are near the community of Green Valley Lake.
QAPP Information: | Sampling and analysis were done according to the SWAMP QAPP. However, in July 2009 an error was discovered in the QAPP related to holding times for total phosphorus samples that affects the validity of data for the Lahontan Region The holding time for samples that are not acid-preserved.should be 48 hours rather than 28 days as indicated in the QAPP. "Low level" phosphorus analyses, without acid preservation, are used in the Lahontan Region's SWAMP program. ..
QAPP Information Reference(s):

DECISION ID | 20878 | Region 6
Crab Creek

Pollutant: | Specific Conductance
Final Listing Decision: | Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: | Do Not List on 303(d) list (TMDL required list)(2010)
Revision Status | Original
Impairment from Pollutant or Pollution: | Pollutant
Regional Board Staff Conclusion: | This pollutant was considered for placement on the section 303(d) list in a previous assessment cycle. No new information was reviewed for this current assessment cycle. Therefore, the previous conclusion remains unchanged, and is as follows: This pollutant is being considered for placement on the section 303(d) list under section 3.2 of the Listing Policy. Under section 3.2 a single line of evidence is necessary to assess listing status. One line of evidence is available in the administrative record to assess this pollutant. None of the samples exceed the water quality objective. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category. This conclusion is based on the staff findings that: 1. The data used satisfy the data quality requirements of section 6.1.4 of the Policy. 2. The data used do not satisfy the data quantity requirements of section 6.1.5 of the Policy. Quarterly samples do not capture the seasonal and annual variability expected in streamflows and constituent concentrations that affect specific conductance in streams of the Lahontan Region. 3. None of 10 samples exceeded the objective and this does not exceed the allowable frequency listed in Table 3.2 of the Listing Policy. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
Regional Board Staff Decision Recommendation: | No new data were assessed for this assessment cycle. The conclusion reached in the previous cycle remains in same. The Regional Board will update this decision when new data and information become available in a future assessment cycle.

Line of Evidence (LOE) for Decision ID 20878, Specific Conductance | Region 6
Crab Creek
LOE ID: | 5218
Pollutant: | Specific Conductance
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | None
Beneficial Use: | Municipal & Domestic Supply
Number of Samples: | 10
Number of Exceedances: | 0
Data and Information Type: | Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: | The U.S. Geological Survey measured specific conductance under the Region 6 SWAMP program between 2001 and 2005. In ten field measurements, specific conductance ranged from 62 to 228 uS/cm. Three additional laboratory measurements had specific conductance ranging from 105 to 228 uS/cm. The MCL was not exceeded.
Data Reference: | 2007. SWAMP Data for the Mojave River Watershed
SWAMP Data: | SWAMP
Water Quality Objective/Criterion: | California Maximum Contaminant Levels (MCLs) apply to ambient waters under the Lahontan Basin Plan's "Chemical Constituents" objective. The MCL for specific conductance is 900 microsiemens per centimeter (uS/cm).
Objective/Criterion Reference: | Water Quality Control Plan for the Lahontan Region (as amended)
Evaluation Guideline: |
Guideline Reference:
Spatial Representation: | One station was sampled (Crab Creek at Crab Flats Road near Lake Arrowhead).
Temporal Representation: | Ten quarterly field measurements (1 to 4 per year) were done between 2001 and 2005. An additional 3 laboratory measurements were done in February and December 2002 and in March 2003.
Environmental Conditions: | Crab Creek is a tributary of Deep Creek, the largest tributary of the Mojave River, located in San Bernardino National Forest. Its headwaters are near the community of Green Valley Lake.
QAPP Information: | Data meet the quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):

DECISION ID | 20803 | Region 6
Crab Creek

Pollutant: | Sulfates
Final Listing Decision: | Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: | Do Not List on 303(d) list (TMDL required list)(2010)
Revision Status | Original
Impairment from Pollutant or Pollution: | Pollutant
Regional Board Staff Conclusion: | This pollutant was considered for placement on the section 303(d) list in a previous assessment cycle. No new information was reviewed for this current assessment cycle. Therefore, the previous conclusion remains unchanged, and is as follows: This pollutant is being considered for placement on the section 303(d) list under section 3.2 of the Listing Policy. Under section 3.2 a single line of evidence is necessary to assess listing status. Two lines of evidence are available in the administrative record to assess this pollutant. None of the samples exceed the applicable water quality objectives. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category. This conclusion is based on the staff findings that: 1. The data used satisfy the data quality requirements of section 6.1.4 of the Policy. 2. The data used do not satisfy the data quantity requirements of section 6.1.5 of the Policy. Quarterly samples do not capture the seasonal and annual variability expected in streamflows and constituent concentrations in streams of the Lahontan Region. 3. None of eleven individual samples or five annual average datapoints exceeded the applicable water quality objectives and this does not exceed the allowable frequency listed in Table 3.2 of the Listing Policy. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
Regional Board Staff Decision Recommendation: | No new data were assessed for this assessment cycle. The conclusion reached in the previous cycle remains in same. The Regional Board will update this decision when new data and information become available in a future assessment cycle.

Line of Evidence (LOE) for Decision ID 20803, Sulfates | Region 6
Crab Creek
LOE ID: | 5220
Pollutant: | Sulfates
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | Dissolved
Beneficial Use: | Municipal & Domestic Supply
Number of Samples: | 11
Number of Exceedances: | 0
Data and Information Type: | Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: | The U.S. Geological Survey sampled sulfate under the Region 6 SWAMP program between 2001 and 2005. Sulfate concentrations in 11 samples ranged from <0.1 to 1.2 mg/L. The MCL was not exceeded.
Data Reference: | 2007. SWAMP Data for the Mojave River Watershed
SWAMP Data: | SWAMP
Water Quality Objective/Criterion: | California Maximum Contaminant Levels apply to ambient waters under the Lahontan Basin Plan's "Chemical Constituents" objective. The MCL for sulfate is 250 mg/L.
Objective/Criterion Reference: | Water Quality Control Plan for the Lahontan Region (as amended)
Evaluation Guideline: |
Guideline Reference:
Spatial Representation: | One station was sampled (Crab Creek at Crab Flats Road near Lake Arrowhead).
Temporal Representation: | Eleven quarterly samples were collected between 2001 and 2005.
Environmental Conditions: | Crab Creek is a tributary of Deep Creek, the largest tributary of the Mojave River, located in San Bernardino National Forest. Its headwaters are near the community of Green Valley Lake. In addition to the Cold Freshwater Habitat beneficial use, Crab Creek is designated for the Spawning, Reproduction and Development use.
QAPP Information: | Data meet the quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):
Line of Evidence (LOE) for Decision ID 20803, Sulfates | Region 6
Crab Creek
LOE ID: | 5219
Pollutant: | Sulfates
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | Dissolved
Beneficial Use: | Cold Freshwater Habitat
Number of Samples: | 5
Number of Exceedances: | 0
Data and Information Type: | Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: | The U.S. Geological Survey sampled sulfate under the Region 6 SWAMP program between 2001 and 2005. Sulfate concentrations in 11 samples ranged from below the detection level to 1.2 mg/L. The annual average objective was not exceeded.
Data Reference: | 2007. SWAMP Data for the Mojave River Watershed
SWAMP Data: | SWAMP
Water Quality Objective/Criterion: | The applicable site-specific objectives are those for Deep Creek Station 5, from Lahontan Basin Plan Table 3-21: The sulfate objective includes an annual average of 1.3 mg/L and a 90th percentile value of 4.9 mg/L.
Objective/Criterion Reference: | Water Quality Control Plan for the Lahontan Region (as amended)
Evaluation Guideline: |
Guideline Reference:
Spatial Representation: | One station was sampled (Crab Creek at Crab Flats Road near Lake Arrowhead).
Temporal Representation: | Eleven quarterly samples were collected between 2001 and 2005.
Environmental Conditions: | Crab Creek is a tributary of Deep Creek, the largest tributary of the Mojave River, located in San Bernardino National Forest. Its headwaters are near the community of Green Valley Lake. In addition to the Cold Freshwater Habitat beneficial use, Crab Creek is designated for the Spawning, Reproduction and Development use.
QAPP Information: | Data meet the quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):

DECISION ID | 21237 | Region 6
Crab Creek

Pollutant: | Temperature, water
Final Listing Decision: | Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: | Do Not List on 303(d) list (TMDL required list)(2010)
Revision Status | Original
Impairment from Pollutant or Pollution: | Pollutant
Regional Board Staff Conclusion: | This pollutant was considered for placement on the section 303(d) list in a previous assessment cycle. No new information was reviewed for this current assessment cycle. Therefore, the previous conclusion remains unchanged, and is as follows: The Lahontan Basin Plan's narrative temperature objective is an antidegradation-based objective that requires that there be no change in temperature in waters designated for the Cold Freshwater Habitat (COLD) beneficial use. The objective does not include specific numerical limits for protection of the COLD use. Listing Policy Section 3.10 contains directions for assessment based on trends in water quality. These directions include requirements to establish specific baseline conditions and specify the influence of seasonal and interannual effects. One line of evidence is available to support this decision. There are not enough temperature samples to establish baseline conditions (including diel, seasonal, annual and interannual variations in temperature) or to detect declining trends in the temperature regime if such trends exist. Because temperature samples were collected only quarterly, weekly and monthly average data are not available for comparison with guidelines in the scientific literature for the temperature requirements of sensitive aquatic species such as salmonids, as directed in Listing Policy Section 6.1.5.9.
Regional Board Staff Decision Recommendation: | No new data were assessed for this assessment cycle. The conclusion reached in the previous cycle remains in same. The Regional Board will update this decision when new data and information become available in a future assessment cycle.

Line of Evidence (LOE) for Decision ID 21237, Temperature, water | Region 6
Crab Creek
LOE ID: | 5223
Pollutant: | Temperature, water
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | None
Beneficial Use: | Cold Freshwater Habitat
Number of Samples: | 11
Number of Exceedances: | 0
Data and Information Type: | Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: | The U.S. Geological Survey measured water temperature under the Region 6 SWAMP program between 2001 and 2005. Eleven temperatures measurements ranged from 2 to 18.5 degrees Celsius.
Data Reference: | 2007. SWAMP Data for the Mojave River Watershed
SWAMP Data: | SWAMP
Water Quality Objective/Criterion: | The applicable language from the Lahontan Basin Plan's temperature objective states: "The natural receiving water temperature of all waters shall not be altered unless it can be demonstrated to the satisfaction of the Regional Board that such an alteration in temperature does not adversely affect the water for beneficial uses. For waters designated WARM, water temperature shall not be altered by more than five degrees Fahrenheit ... above or below the natural temperature. For waters designated COLD, the temperature shall not be altered."
Objective/Criterion Reference: | Water Quality Control Plan for the Lahontan Region (as amended)
Evaluation Guideline: |
Guideline Reference:
Spatial Representation: | One station was sampled (Crab Creek at Crab Flats Road near Lake Arrowhead).
Temporal Representation: | Eleven quarterly water temperature measurements (1 to 4 per year) were taken between 2001 and 2005.
Environmental Conditions: | Crab Creek is a tributary of Deep Creek, the largest tributary of the Mojave River, located in San Bernardino National Forest. Its headwaters are near the community of Green Valley Lake. In addition to the Cold Freshwater Habitat beneficial use, Crab Creek is designated for the Spawning, Reproduction and Development use.
QAPP Information: | Data meet the quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):

DECISION ID | 21808 | Region 6
Crab Creek

Pollutant: | Total Kjeldahl Nitrogen (TKN)
Final Listing Decision: | Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: | Do Not List on 303(d) list (TMDL required list)(2010)
Revision Status | Original
Impairment from Pollutant or Pollution: | Pollutant
Regional Board Staff Conclusion: | This pollutant was considered for placement on the section 303(d) list in a previous assessment cycle. No new information was reviewed for this current assessment cycle. Therefore, the previous conclusion remains unchanged, and is as follows: This pollutant is being considered for placement on the section 303(d) list under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status. One line of evidence is available in the administrative record to assess this pollutant. No biological data are available to assess whether the chemical samples exceed the water quality objective for biostimulatory substances. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category. This conclusion is based on the staff findings that: 1. The data used satisfy the data quality requirements of section 6.1.4 of the Policy. 2. The data used do not satisfy the data quantity requirements of section 6.1.5 of the Policy. Quarterly samples do not capture the seasonal and annual variability expected in streamflows and constituent concentrations in streams of the Lahontan Region. 3. Biological data were not available to assess whether any of the 11 chemical samples exceeded the water quality objective for biostimulatory substances. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
Regional Board Staff Decision Recommendation: | No new data were assessed for this assessment cycle. The conclusion reached in the previous cycle remains in same. The Regional Board will update this decision when new data and information become available in a future assessment cycle.

Line of Evidence (LOE) for Decision ID 21808, Total Kjeldahl Nitrogen (TKN) | Region 6
Crab Creek
LOE ID: | 7804
Pollutant: | Total Kjeldahl Nitrogen (TKN)
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | Total
Beneficial Use: | Cold Freshwater Habitat
Number of Samples: | 11
Number of Exceedances: | 0
Data and Information Type: | Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: | The U.S. Geological Survey sampled Crab Creek under the Region 6 SWAMP program between 2002 and 2005. Eleven quarterly samples were collected. One sample was below the detection level, and two samples were estimated values. Concentrations of TKN in the remaining samples ranged from 0.1 to 0.23 mg/L. No data on algae or macrophytes are available for assessment of compliance with the biostimulatory substances objective.
Data Reference: | 2007. SWAMP Data for the West Walker River and East Walker River Hydrologic Units
| 2007. SWAMP Data for the Mojave River Watershed
SWAMP Data: | SWAMP
Water Quality Objective/Criterion: | The Lahontan Basin Plan does not include a site-specific objective (SSO) for total Kjeldahl nitrogen (TKN) in Crab Creek. (The SSO for nitrate is assessed in a separate line of evidence.) The narrative objective for biostimulatory substances states: "Waters shall not contain biostimulatory substances in concentrations that promote aquatic growths to the extent that such growths cause nuisance or adversely affect the water for beneficial uses."
Objective/Criterion Reference: | Water Quality Control Plan for the Lahontan Region (as amended)
Evaluation Guideline: |
Guideline Reference:
Spatial Representation: | One station was sampled (Crab Creek at Crab Flats Road near Lake Arrowhead).
Temporal Representation: | Eleven quarterly samples (1 to 3 per year) were collected between 2001 and 2005.
Environmental Conditions: | Crab Creek is a tributary of Deep Creek, the largest tributary of the Mojave River, located in San Bernardino National Forest. Its headwaters are near the community of Green Valley Lake.
QAPP Information: | Data meet the quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):

DECISION ID | 21736 | Region 6
Crab Creek

Pollutant: | Total Nitrogen as N
Final Listing Decision: | Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: | Do Not List on 303(d) list (TMDL required list)(2010)
Revision Status | Original
Impairment from Pollutant or Pollution: | Pollutant
Regional Board Staff Conclusion: | This pollutant was considered for placement on the section 303(d) list in a previous assessment cycle. No new information was reviewed for this current assessment cycle. Therefore, the previous conclusion remains unchanged, and is as follows: This pollutant is being considered for placement on the section 303(d) list under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status. One line of evidence is available in the administrative record to assess this pollutant. None of the annual average datapoints exceed the water quality objective. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category. This conclusion is based on the staff findings that: 1. The data used satisfy the data quality requirements of section 6.1.4 of the Policy. 2. The data used do not satisfy the data quantity requirements of section 6.1.5 of the Policy. Quarterly samples do not capture the seasonal and annual variability expected in streamflows and constituent concentrations in streams of the Lahontan Region. 3. None of 5 annual average datapoints exceeded the site-specific objective and this does not exceed the allowable frequency listed in Table 3.1 of the Listing Policy. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
Regional Board Staff Decision Recommendation: | No new data were assessed for this assessment cycle. The conclusion reached in the previous cycle remains in same. The Regional Board will update this decision when new data and information become available in a future assessment cycle.

Line of Evidence (LOE) for Decision ID 21736, Total Nitrogen as N | Region 6
Crab Creek
LOE ID: | 7811
Pollutant: | Total Nitrogen as N
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | Total
Beneficial Use: | Cold Freshwater Habitat
Number of Samples: | 5
Number of Exceedances: | 0
Data and Information Type: | Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: | The U.S. Geological Survey sampled Crab Creek under the Region 6 SWAMP program between 2001 and 2005. Eleven quarterly samples were collected for total Kjeldahl nitrogen, and 11 samples for nitrite plus nitrate. Total nitrogen was calculated from these sampling results. Annual average concentrations of total nitrogen ranged from 0 in 2002 (when all samples were estimates or below the detection level) to 0.209 in 3003. The objective was not exceeded.
Data Reference: | 2007. SWAMP Data for the Mojave River Watershed
SWAMP Data: | SWAMP
Water Quality Objective/Criterion: | The site-specific objective for total nitrogen is the objective for Deep Creek Station 5 in Table 3-21 of the Lahontan Basin Plan. The objective includes an annual average of average of 0.3 mg/L and a 90th percentile value of 0.7 mg/L.
Objective/Criterion Reference: | Water Quality Control Plan for the Lahontan Region (as amended)
Evaluation Guideline: |
Guideline Reference:
Spatial Representation: | One station was sampled (Crab Creek at Crab Flats Road near Lake Arrowhead).
Temporal Representation: | Eleven quarterly samples (1 to 3 per year) were collected for total Kjeldahl nitrogen, and eleven for nitrite plus nitrate, between 2001 and 2005. Eleven calculations for total nitrogen were done, and five annual averages were calculated.
Environmental Conditions: | Crab Creek is a tributary of Deep Creek, the largest tributary of the Mojave River, located in San Bernardino National Forest. Its headwaters are near the community of Green Valley Lake.
QAPP Information: | Data meet the quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):

DECISION ID | 21796 | Region 6
Crab Creek

Pollutant: | pH
Final Listing Decision: | Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: | Do Not List on 303(d) list (TMDL required list)(2010)
Revision Status | Original
Impairment from Pollutant or Pollution: | Pollutant
Regional Board Staff Conclusion: | This pollutant was considered for placement on the section 303(d) list in a previous assessment cycle. No new information was reviewed for this current assessment cycle. Therefore, the previous conclusion remains unchanged, and is as follows: The Lahontan Basin Plan's narrative pH objective is an antidegradation-based objective that requires that there be no change greater than 0.5 pH units in waters designated for the Cold Freshwater Habitat (COLD) or Warm Freshwater Habitat beneficial uses. Listing Policy Section 3.10 contains directions for assessment based on trends in water quality. These directions include requirements to establish specific baseline conditions and specify the influence of seasonal and interannual effects. One line of available to support this decision. There are not enough pH samples to establish baseline conditions (including diel, seasonal, annual and interannual variations) or to detect changes in the pH regime due to controllable factors, if such trends exist.
Regional Board Staff Decision Recommendation: | No new data were assessed for this assessment cycle. The conclusion reached in the previous cycle remains in same. The Regional Board will update this decision when new data and information become available in a future assessment cycle.

Line of Evidence (LOE) for Decision ID 21796, pH | Region 6
Crab Creek
LOE ID: | 5216
Pollutant: | pH
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | None
Beneficial Use: | Cold Freshwater Habitat
Number of Samples: | 11
Number of Exceedances: | 0
Data and Information Type: | Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: | The U.S. Geological Survey measured pH quarterly under the Region 6 SWAMP program between 2001 and 2005. The pH in 11 field measurements ranged from 7.2 to 8.2 units.
Data Reference: | 2007. SWAMP Data for the Mojave River Watershed
SWAMP Data: | SWAMP
Water Quality Objective/Criterion: | The Lahontan Basin Plan's regionwide objective for pH states: "In fresh waters with designated beneficial uses of COLD or WARM, changes in normal ambient pH levels shall not exceed 0.5 pH units. For all other waters of the region, the pH shall not be depressed below 6.5 nor raised above 8.5 units. The Regional Board recognizes that some waters of the Region may have natural pH levels outside of the 6.5 to 8.5 range. Compliance with the pH objective for these waters will be determined on a case-by-case basis."
Objective/Criterion Reference: | Water Quality Control Plan for the Lahontan Region (as amended)
Evaluation Guideline: |
Guideline Reference:
Spatial Representation: | One station was sampled (Crab Creek at Crab Flats Road near Lake Arrowhead).
Temporal Representation: | Eleven field pH measurements were taken between 2001 and 2005.
Environmental Conditions: | Crab Creek is a tributary of Deep Creek, the largest tributary of the Mojave River, located in San Bernardino National Forest. Its headwaters are near the community of Green Valley Lake. In addition to the Cold Freshwater Habitat beneficial use, Crab Creek is designated for the Spawning, Reproduction and Development use.
QAPP Information: | Data meet the quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):

DECISION ID | 30157 | Region 6
Crab Creek

Pollutant: | Total Dissolved Solids
Final Listing Decision: | List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: | List on 303(d) list (TMDL required list)(2010)
Revision Status | Original
Sources: | Source Unknown
Expected TMDL Completion Date: | 2021
Impairment from Pollutant or Pollution: | Pollutant
Regional Board Staff Conclusion: | This pollutant was considered for placement on the section 303(d) list in a previous assessment cycle. No new information was reviewed for this current assessment cycle. Therefore, the previous conclusion remains unchanged, and is as follows: Regional Board Conclusion: This pollutant is being considered for placement on the section 303(d) list under section 3.2 of the Listing Policy. Under section 3.2 a single line of evidence is necessary to assess listing status. Two lines of evidence are available in the administrative record to assess this pollutant. None of the samples exceeds the California Maximum Contaminant Level (MCL). Five of five annual average datapoints exceed the site-specific water quality objective. However, listing is not being recommended because the data are not temporally representative. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category. This conclusion is based on the staff findings that: 1. The data used satisfy the data quality requirements of section 6.1.4 of the Policy. 2. The data used do not satisfy the data quantity requirements of section 6.1.5 of the Policy. Quarterly samples do not capture the full range of seasonal and annual variability in streamflows and constituent concentrations expected in waters of the Lahontan Region. 3. None of 11 individual samples exceeded the California MCL and this does not exceed the allowable frequency listed in Table 3.2 of the Listing Policy. Five out of five annual average datapoints exceeded the site specific objective and this exceeds the allowable frequency listed in Table 3.2 of the Listing Policy. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met. State Board Review and Conclusion: The April 19, 2010 State Water Board staff report for the 2010 Integrated Report recommended to place this water body on the 303(d) list for total dissolved solids based on the State Water Board staff determination that the data were collected over a broad period of time to meet section 6.1.5.3 of the Listing Policy. The State Board recommendation is based on the following: Lahontan Regional Board staff had decided not to list this water body because staff thought it had insufficient information to make a decision to list. However, State Board staff finds there are 11 samples to make a decision and this meets the sample size requirements of Table 3.2 of the Listing Policy. On August 4, 2010 the State Water Board approved the staff recommendation to place this water body-pollutant combination on the 303(d) list. The final language for the recommendation is: Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification in favor of placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category. This conclusion is based on the staff findings that: 1. The data used satisfy the data quality requirements of section 6.1.4 of the Policy. 2. The data used satisfy the data quantity requirements of section 6.1.5 of the Policy. 3. None of 11 individual samples exceeded the California MCL and this does not exceed the allowable frequency listed in Table 3.2 of the Listing Policy. Five out of five annual average datapoints exceeded the site specific objective and this exceeds the allowable frequency listed in Table 3.2 of the Listing Policy. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
Regional Board Staff Decision Recommendation: | No new data were assessed for this assessment cycle. The conclusion reached in the previous cycle remains in same. The Regional Board will update this decision when new data and information become available in a future assessment cycle.

Line of Evidence (LOE) for Decision ID 30157, Total Dissolved Solids | Region 6
Crab Creek
LOE ID: | 5222
Pollutant: | Total Dissolved Solids
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | Total Dissolved
Beneficial Use: | Municipal & Domestic Supply
Number of Samples: | 11
Number of Exceedances: | 0
Data and Information Type: | Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: | The U.S. Geological Survey sampled TDS under the Region 6 SWAMP program between 2001 and 2005. TDS concentations in 11 samples ranged from 68 to 176 mg/L. The MCL was not exceeded.
Data Reference: | 2007. SWAMP Data for the Mojave River Watershed
SWAMP Data: | SWAMP
Water Quality Objective/Criterion: | California Maximum Contaminant Levels (MCLs) apply to ambient waters under the Lahontan Basin Plan's "Chemical Constituents" objective. The MCL for Total Dissolved Solids (TDS) is 500 mg/L.
Objective/Criterion Reference: | Water Quality Control Plan for the Lahontan Region (as amended)
Evaluation Guideline: |
Guideline Reference:
Spatial Representation: | One station was sampled (Crab Creek at Crab Flats Road near Lake Arrowhead).
Temporal Representation: | Eleven quarterly samples were collected between 2001 and 2005.
Environmental Conditions: | Crab Creek is a tributary of Deep Creek, the largest tributary of the Mojave River, located in San Bernardino National Forest. Its headwaters are near the community of Green Valley Lake. In addition to the Cold Freshwater Habitat beneficial use, Crab Creek is designated for the Spawning, Reproduction and Development use.
QAPP Information: | Data meet the quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):
Line of Evidence (LOE) for Decision ID 30157, Total Dissolved Solids | Region 6
Crab Creek
LOE ID: | 5221
Pollutant: | Total Dissolved Solids
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | Total Dissolved
Beneficial Use: | Cold Freshwater Habitat
Number of Samples: | 5
Number of Exceedances: | 5
Data and Information Type: | Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: | The U.S. Geological Survey sampled TDS under the Region 6 SWAMP program between 2001 and 2005. TDS concentations in 11 individual samples ranged from 68 to 176 mg/L. Annual averages (calculated from 1 to 3 samples per year) ranged from 90 to 176 mg/L. The highest "average" was based on a single sample. The annual average objective was exceeded in five out of five years.
Data Reference: | 2007. SWAMP Data for the Mojave River Watershed
SWAMP Data: | SWAMP
Water Quality Objective/Criterion: | The applicable site-specific objectives are those for Deep Creek Station 5, from Lahontan Basin Plan Table 3-21. The objective for Total Dissolved Solids (TDS) includes an annual average of 83 mg/L and a 90th percentile value of 123 mg/L.
Objective/Criterion Reference: | Water Quality Control Plan for the Lahontan Region (as amended)
| 2007. SWAMP Data for the Mojave River Watershed
Evaluation Guideline: |
Guideline Reference:
Spatial Representation: | One station was sampled (Crab Creek at Crab Flats Road near Lake Arrowhead).
Temporal Representation: | Eleven quarterly samples (1 to 3 per year) were collected between 2001 and 2005. Five annual average calculations were done.
Environmental Conditions: | Crab Creek is a tributary of Deep Creek, the largest tributary of the Mojave River, located in San Bernardino National Forest. Its headwaters are near the community of Green Valley Lake. In addition to the Cold Freshwater Habitat beneficial use, Crab Creek is designated for the Spawning, Reproduction and Development use.
QAPP Information: | Data meet the quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):